• Journal of Biosystems Engineering
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• v.35 no.5
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• pp.357-365
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• 2010

Workers in the agricultural industry have been exposed to many work-related musculoskeletal disorders. So, our objectives in this study were to measure and analyze worker's physiological bio-information to reduce musculoskeletal disorders in relation to agricultural works. We investigated worker's bio-information of physiological signals during the repeated lifting work such as body temperature, heart rate, blood pressure, physical activity, and heart rate variability. Moreover, we analyzed the workloads of lumbar spine during the repeated lifting work using the 3-axis acceleration and angular velocity sensors. The changes of body temperature was not significant, but the mean heart rate increased from 90/min to 116/min significantly during 30 min of repeated lifting work (p<0.05). The average worker's physical activity(energy consumption rate) was 206 kcal/70kg/h during the repeated lifting work. The workers' acute stress index was more than 80, which indicated a stressful work. Also, the maximum shear force on the disk (L5/S1) of a worker's lumbar spine in static state was 500N, and the maximum inertia moment was 139 $N{\cdot}m$ in dynamic state.

• Journal of Embryo Transfer
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• v.29 no.2
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• pp.171-175
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• 2014

This study was conducted to determine the efficacy of anthelmintics against gastrointestinal parasitic infestation in periparturient dairy cows and its effect on milk yield and quality. Sixty pregnant cows of 1st & 2nd parity were divided into four groups. The efficacy of anthelmintic treatment was evaluated by counting faecal egg per gram (EPG) compared with pre-treatment values. The milk yield of each cow was recorded in pre and post treatment lactations. Cows of group A were treated with Nitroxynil 10 mg/kg body weight subcutaneously 30 days before parturition, group B were treated with combination of triclabendazole and levamisole 19.5 mg/kg body weight orally at calving and group C treated with $Endex^{(R)}$ at calving and 42 days after. The mean change in EPG 14 days after treatment was significantly higher (p<0.05) in treated (79.1%) cows than control. Average milk yield of group C ($2.8{\pm}0.8$) was significantly higher (p<0.01) than group A ($2.6{\pm}0.7$). Similarly, the average milk yield in all the treated cows was significantly (p<0.01) higher in treated lactation ($2.5{\pm}0.7$) than in the previous lactation ($2.2{\pm}0.7$). The average milk yield in all treated cows was significantly (p<0.01) higher than the control cows. Although, milk yields were higher in second parity than the first, there was no significant difference (p>0.05). The milk protein percentage was significantly higher (p<0.05) in treated group than the control group. Therefore, it may be concluded that periparturient anthelmintic treatment effectively reduced the gastrointestinal parasitic load and improved milk yield.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.33 no.12
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• pp.76-82
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• 2005

An experimental study on an axial-type micro turbine which consists of maximum 6 stages is conducted to measure aerodynamic characteristics on each stage. This turbine has a 2.0 flow coefficient, 3.25 loading coefficient and 25.8mm mean diameter. The solidity of stators and rotors is within a 0.67~0.75, and the off-design performance is measured by changing the load after adjusting the mass flowrate and the total pressure to constant at inlet. A maximum specific output power of 2kW/kg/sec is obtained in one stage, but the increment of the specific output power with increasing stages is alleviated. In case of torque, the increment of the torque maintains to constant at low RPM region, but its increment become dull at high RPM region. The efficiency of the micro turbine becomes low because the tip gap effect is great due to the small blade, but it could be improved by increasing the stages.

• Journal of Nutrition and Health
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• v.35 no.1
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• pp.78-89
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• 2002

This study was performed to analyse some rick ffactors for chronic degenerative diseases of the Korean dict. The study subjects consisted of preschool children(PC), elementary school children(EC), high school students(HS), college students(CS), and adults over 30 years old living in Seoul and the surrounding areas. The subjects over 30 years old were classfied to 30-49 years, 50-69 years, and over 70 years. A dietary survey was conducted using 24-hour recall method and data were collected from 2392 subjects. The dietary risks for chronic degenerative disease such as food sources of fat consumption, high cholesterol intake, low dietary fiber intake, and low calcium intake and high protein intake were analyzed. Younger subjects had more animal fat proportion than older subjects did. HS and CS had the least fat proportion from fishes and shellfishes. Each mean cholesterol intake of PC, EC, HS, and CS was over 300mg/day, and HS load the highest level of 415mg/day. Cholesterol density of the diet of PC was the highest of 175mg/1000kcal and the level decreased when the age increased. The subjects consuming cholesterol over 100 mg/1000kca1 were about 70% of PC and HS. More than 20% of PC, EC, and HS consumed calcium under 75% of RDA with protein consumption over 125% of RDA. Dietary fiber intakes were 18g for HS, CS, 30-49 years, and 50 ∼ 69 years, 14g for EC and over 70 years, and 12g for PC. Ninety percent of PC and EC, 80% of HS and CS, and 70% of tole subjccts over 30years consumed dietary fiber under the level of 10g/1000kca1. The major food sources of dietary fiber were vegetables and grains. From these results, children and adolescents had ricks for chronic degenerative diseases on all the analyzed items. The results of this study would provide the basic information for development of dietary interventions to improve diet find health.

• Advances in biomechanics and applications
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• v.1 no.3
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• pp.169-185
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• 2014

Computational multibody models of the elbow can provide a versatile tool to study joint mechanics, cartilage loading, ligament function and the effects of joint trauma and orthopaedic repair. An efficiently developed computational model can assist surgeons and other investigators in the design and evaluation of treatments for elbow injuries, and contribute to improvements in patient care. The purpose of this study was to develop an anatomically correct elbow joint model and validate the model against experimental data. The elbow model was constrained by multiple bundles of non-linear ligaments, three-dimensional deformable contacts between articulating geometries, and applied external loads. The developed anatomical computational models of the joint can then be incorporated into neuro-musculoskeletal models within a multibody framework. In the approach presented here, volume images of two cadaver elbows were generated by computed tomography (CT) and one elbow by magnetic resonance imaging (MRI) to construct the three-dimensional bone geometries for the model. The ligaments and triceps tendon were represented with non-linear spring-damper elements as a function of stiffness, ligament length and ligament zero-load length. Articular cartilage was represented as uniform thickness solids that allowed prediction of compliant contact forces. As a final step, the subject specific model was validated by comparing predicted kinematics and triceps tendon forces to experimentally obtained data of the identically loaded cadaver elbow. The maximum root mean square (RMS) error between the predicted and measured kinematics during the complete testing cycle was 4.9 mm medial-lateral translational of the radius relative to the humerus (for Specimen 2 in this study) and 5.30 internal-external rotation of the radius relative to the humerus (for Specimen 3 in this study). The maximum RMS error for triceps tendon force was 7.6 N (for Specimen 3).

• The Journal of the Korea Contents Association
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• v.15 no.4
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• pp.545-555
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• 2015

We investigated the influence of negative emotion such as state-trait anxiety and depression and working memory (WM) on Foreign Language Vocabulary Learning (FLVL) of South Korean university students. Also, its implications for developing contents for FLVL were discerned. To do so, state-trait anxiety and depression inventories as well as four kinds of WM test were performed for 132 undergraduate students. Participants also had two semantic learning sessions for Swahili words. The mean scores of negative emotions were normal level. The results of structural equation modeling (SEM) showed that there was no effect of negative emotion on FLVL, while direct effects of the negative emotion on WM and the WM on FLVL were significant. Such results suggested that FLVL would be weakened, with the result that WM had been impaired by negative emotions. These outcomes suggested that when developing FLVL content for university students, it is necessary to consider the negative emotions of foreign language learners and to develop the contents for FLVL in the light of WM load.

• Journal of Nutrition and Health
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• v.30 no.10
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• pp.1180-1187
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• 1997

Cigarette smoking is a major risk factor of atherosclerosis and has been reported to contain an abundance of free radical species which could be expected to deplete antioxidants such as vitamin C . The present study was designed to investigate the relationship between smoking, plasma lipid and lipoprotein concentration, and plasma vitamin C level. Fifty-five healthy male smokers and 32 non-smokers were investigated in the study. Mean age, body weight , BMI and blood pressure made no differences in both smokers and non-smokers. Significantly, smokers has higher plasma total cholesterol and LDL-C , and lower HDL-C /LDL-C ratio compared with non-smokers. Plasma level of thiobartiturin acid reactive substances(TBARS), indicator of lipid peroxidation and increased susceptibility of LDL towards lipid perosidation, were elevated in smokers(p<0.001), while the plasma vitamin C level of smokers was significantly lower than that of non-smokers(p<0.05), indicating that elevated lipid peroxidation are associated with decreased plasma vitamin C content. In non-smokers a significantly positive correlation was observed between dietary vitamin C intake and plasma levels, but no such association observed in smokers. Lack of such a relationship and the decreased plasma vitamin C level in the smokers suggest that smoking may cause increased turnover of the plasma antioxidant. Consuquently, the sustained free radical load derived from smoking causes an imbalance in oxidant/antioxidant status and it could be expected that cigarette smoking renders plasma LDL more susceptible to oxidative modification . In the present study the possible explanations for that cigarette smokers have a higher risk of cardiovascular disease include the changes of blood lipid and lipoprotein concentration, and plasma vitamin C status which might have protective functions against free radicals -medaited lipid peroxidation.

• Proceedings of the KIEE Conference
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• 2005.11b
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• pp.145-147
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• 2005

This paper presents a methodology for satisfying the thermal comfort of Indoor environment and reducing the summer peak demand power by minimizing the power consumption for an Air-conditioner within a space. KEPCO(Korea Electric Power Corporation) use the fixed duty cycle control method regardless of the indoor thermal environment. This method has disadvantages that energy saying depends on the set-point value of the Air-Conditioner and DLC has no net effects on Air-conditioners if the appliance has a lower operating cycle than the fixed duty cycle. A variable duty cycle estimates the PMV(Predict Mean Vote) at the next step with a predicted temperature and humidity coming from the back propagation neural network model. It is possible to reduce the energy consumption by maintaining the Air-conditioner's OFF state when the PMV lies in the thermal comfort range. The proposed methodology uses the historical real data of Sep. 7th, 2001 from a classroom in seoul to verify the effectiveness of the variable duty cycle method comparing with fixed duty cycle. The result shows that the variable duty cycle reduces the peak demand to 2.6times more than fixed duty cycle and increases the load control ratio by 8% more. Based on the variable duty cycle control algorithm, the effectiveness of DLC is much more improved as compared with the fixed duty cycle.

• Journal of Korean Society on Water Environment
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• v.24 no.3
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• pp.333-339
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• 2008

This study was carried out to assay the relationships between empirical factors and water quality in 23 agricultural reservoirs. Based on the trophic state index (TSI) deviation analysis, phosphorus in type II and III was the primary limiting factor on algal growth. BOD, COD, TP and chl.a concentration in type III reservoirs showed higher concentration than those of other types, while SS and TN concentration was no noticeable difference among three types. Characteristics of type III reservoirs showed large reservoir surface and drainage area, large surface area to volume (SAV) ratio, small drainage area to reservoir area (DA/RA) ratio, relatively old age, large paddy field and upland field to drainage area ratio (Mean 17.4%) and high generation and discharge loads compared to other types of reservoirs. In type I and II reservoirs, trends of BOD, TN, TP concentration in water column, were similar to those of the discharge load of pollutants. Although type II reservoirs generally showed low phosphorus discharge loads compared to type I reservoirs, TP and chl.a concentration in water column was greater than that of type I. Characteristics of type II reservoirs showed relatively large SAV ratio and old age compared to type I reservoirs and was similar to those of type III including eutrophic reservoirs.

• Journal of Korean Society of Water and Wastewater
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• v.23 no.5
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• pp.599-608
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• 2009

This manuscript covers the results of field investigation and lab-scale experiments to design a double-layered biofilter system to control urban storm runoff. The biofilter system consisted of a coarse soil layer (CSL) for filtration and fine soil layer (FSL) for adsorption and biological degradation. The variations of flow rate and water quality of runoff from a local expressway were monitored for seven storm events. Laboratory column experiments were performed using seven kinds of soil and mulch to maximize pollutants removal. The site mean concentration (SMC) of storm runoff from the drainage area (runoff coefficient: 0.92) was measured to be 203 mg/L for SS, 307 mg/L for $TCOD_{Cr}$, 12.3 mg/L for TN, 7.3 mg/L for ${NH_4}^+-N$, and 0.79 mg/L for TP, respectively. This study employed a new design concept, to cover the maximum rainfall intensity with one month recurrence interval. Effective storms for last ten years (1998-2007) in seoul suggested the design rainfull intensity to be 8.8 mm/hr Single layer soil column showed the maximum removal rate of pollutants load when the uniformity coefficient of CSL was 1.58 and the silt/clay contents of FSL was virtually 7%. The removal efficiency during operation of double layer soil column was 98% for SS and turbidity, 75% for TCODCr, 56% for ${NH_4}^+-N$, 87% for TP, and 73-91% for heavy metals. The hydraulic conductivity of the soil column, 0.023 cm/sec, suggested that the surface area of the biofilter system should be about 1% of the drainage area to treat the rainfall intensity of one month recurrence interval.